Matching data I/O types on backplane systems

ABSTRACT

Various examples described herein provide for determining a first data input/output (I/O) type of a computing device module and a second data I/O type of an I/O switch module, where the computing device module and the I/O switch module are coupled through a backplane system that includes a retimer. In response to the first data I/O type matching the second data I/O type, a connection between the computing device module and the I/O switch module may be permitted or prevented via the retimer.

BACKGROUND

For certain server configurations, such as density-optimized serverracks, input/output (I/O) switch units (e.g., high-speed I/O fabricswitch) are traditionally utilized to facilitate communications betweendifferent computing device modules (e.g., server blades or cartridges).Generally, the I/O switch unit is installed at the top of the serverrack. To meet customer demands for additional compute density within theserver rack, the I/O switch may be integrated directly into a computersystem enclosure of the server rack that receives the individualcomputing device modules. Space freed by this integration can bereallocated to additional computer system enclosures.

To integrate the I/O switch into a computer system enclosure, thecomputer system enclosure can include an active backplane that canprovide an internal connection between a computing device module (e.g.,a server blade or cartridge plugged into one side of the computer systemenclosure) and a I/O switch disposed within the computer systemenclosure (e.g., opposite to the server blade).

BRIEF DESCRIPTION OF THE DRAWINGS

Certain examples are described in the following detailed description inreference to the following drawings.

FIGS. 1 and 2 are block diagrams illustrating example computingenvironments including example backplane systems according to thepresent disclosure.

FIG. 3 is a block diagram illustrating an example computer systemenclosure including an example backplane system according to the presentdisclosure.

FIG. 4 is a block diagram illustrating an example computing environmentincluding an example backplane system according to the presentdisclosure.

FIG. 5 is a block diagram illustrating an example computer systemenclosure including an example backplane system according to the presentdisclosure.

FIGS. 6 and 7 flow diagrams illustrating example methods for backplanesystems according to the present disclosure.

DETAILED DESCRIPTION

As noted, an active backplane in a computer system enclosure can permitintegration of an I/O switch and can easily and simply permit aninternal connection between a computing device module and aninput/output (I/O) switch disposed within the computer system enclosure.Unfortunately, such an integration also makes it possible for anindividual to connect a computing device module with one data I/O type(e.g., a first fabric type) through the backplane to an I/O switchmodule that supports a completely different data I/O type (e.g., asecond fabric type). This mismatch in data I/O types can causecommunication errors, or even worse, electrical damage to the switchmodule or the computing device module if nothing is done to disconnectthe incompatible data I/O types.

Various examples described herein prevent a connection (through abackplane system) between a computing device module (e.g., server bladeor cartridge) and an I/O switch module (e.g., Ethernet fabric switch)involving incompatible data I/O types. In particular, some examplesprevent an incompatible connection between a computing device module andan I/O switch module when a data I/O type utilized by the computingdevice module does not match a data I/O type supported by the I/O switchmodule.

To achieve this, some examples described herein utilize a backplanesystem that includes a retimer to couple a computing device module withan I/O switch module. The backplane system may determine a first datainput/output (I/O) type of a computing device module (e.g., supported bythe computing device module) and may determine a second data I/O type ofan I/O switch module (e.g., supported by the I/O switch module. Inresponse to the first data I/O type matching the second data I/O type,the backplane system may permit or prevent a connection between thecomputing device module and the I/O switch module via the retimer.

As used herein, a retimer can include a signal retimer that can send orreceive data signals (e.g., over a data bus) with respect to a hardwarecomponent (e.g., application-specific integrated circuit [ASIC]).Additionally, as used herein, modules and other components of variousexamples may comprise, in whole or in part, hardware (e.g., electroniccircuitry), or a combination of hardware and programming (e.g.,machine-readable instructions, such as firmware), to implementfunctionalities described herein. For instance, a module may comprise acombination of machine-readable instructions, stored on at least onenon-transitory machine-readable storage medium, and at least oneprocessing resource (e.g., controller) to execute those instructions.The machine-readable instructions may comprise computer-readableinstructions executable by a processor to perform a set of functions inaccordance with various examples described herein. In another instance,a module may comprise electronic circuitry to perform a set of functionsin accordance with various examples described herein.

The following provides a detailed description of examples illustrated byFIGS. 1-7.

FIG. 1 is a block diagram illustrating an example computing environment100 including an example backplane system 104 according to the presentdisclosure. As shown, the example computing environment 100 includes acomputing device module 102, a backplane system 104, and an input/output(I/O) switch module 106. For various examples, the backplane system 104is included within a computer system enclosure (e.g., chassis includinga set of server trays), which may be capable of physically receiving thecomputing device module 102, the I/O switch module 106, or both. Thecomputing device module 102 may physically couple to the backplanesystem 104 when the computing device module 102 is received by (e.g.,inserted into) the computer system enclosure, and the I/O switch module106 may physically couple to the backplane system 104 when the I/Oswitch module 106 received by (e.g., inserted into) the computer systemenclosure. The backplane system 104 may be a component of a computersystem, such a desktop, laptop, workstation, server (e.g., rack-mountserver), or other device operated by a processor, and a computer systemenclosure including the backplane system 104 may be part of such acomputer system. For instance, the backplane system 104 may be part of ablade server computer system enclosure, where the computing devicemodule 102 may comprise a blade server, and the I/O switch module 106may comprise a I/O fabric switch. In various examples, the components orthe arrangement of components in the backplane system 104 may differfrom what is depicted in FIG. 1.

According to various examples, after each is coupled to the backplanesystem 104, the computing device module 102 and the I/O switch module106 can exchange data through the backplane system 104. Depending on theexample, the computing device module 102 can comprise a compute blade(e.g., server blade), compute cartridge (e.g., server cartridge), oranother modular processor-based device that can be inserted (e.g.,plugged) into a computer system enclosure (not shown) that includes thebackplane system 104. For some examples, the computing device module 102includes a physical connector (e.g., male or female media connector)that facilitates physically coupling with the backplane system 104.Through the backplane system 104, the computing device module 102 maycommunicate with the I/O switch module 106 using a number of data I/Otypes, including InfiniBand (e.g., EDR IB), INTEL Omni-Path, Ethernet,or the like, at different data rates (e.g., 100 Gb), which may besupported by the I/O switching module 106. For various examples, morethan one computing device module can physically couple to the backplanesystem 104 and communicate with the I/O switch module 106, therebyfacilitating data exchange (e.g., I/O data exchange) between thecomputing device modules (e.g., 102 and another computing device module)by way of the I/O switch module 106.

The I/O switch module 106 may comprise a data switch (e.g., networkswitch) capable exchanging data with two or more computing devicescommunicating with the I/O switch module 106. As noted herein, thecomputing device module 102 (and the like) can communicate with the I/Oswitch module 106 through the backplane system 104. To communicate witha computing device, the data switch may support a set of I/O data typesincluding, but not limited to, InfiniBand (e.g., EDR IB), INTELOmni-Path, Ethernet, and the like, at different data rates (e.g., 100Gb), which may be supported by the I/O switching module 106. Forinstance, the I/O switch module 106 may comprise a 10 Gb Ethernetswitch. Depending on the example, the backplane system 104 may couple toa plurality of I/O switch modules, which may support common or differentI/O types. After coupling to the backplane system 104 within a computersystem enclosure, the I/O switch module 106 can operate as an integratedI/O switch for various computing devices coupling to the backplanesystem 104.

In FIG. 1, the backplane system 104 comprises a backplane 108, a retimer110, and a controller 112 for enabling and disabling the retimer 110 inresponse to a data I/O type match. Additionally, as shown, the backplane108 includes a first physical connector 114 and a second physicalconnector 116. For some examples, the retimer 110, the controller 112,or both are included by the backplane 108 (e.g., disposed thereon). Forinstance, the retimer 110 may be disposed on the backplane 108, betweenthe first physical connector 114 and the second physical connector 116,thereby permitting it to be included in the data signal path between thetwo connectors.

The backplane 108 may comprise a printed circuit board that includes aset of printed circuit board traces (e.g., data bus lanes) thatphysically couple the first physical connector 114 with the retimer 110,and a set of printed circuit board traces (e.g., data bus lanes) thatthat physically couple the second physical connector 116 with theretimer 110. For various examples, the first physical connector 114 isdisposed on the backplane 108 such that the computing device module 102can physically couple to the first physical connector 114 (e.g., at theback end of a server tray). Similarly, the second physical connector 116is disposed on the backplane 108 such that the I/O switch module 106 canphysically couple to the second physical connector 116 (e.g., sideopposite a server tray). Additionally, for various examples, the retimer110 is included as part of the backplane 108 (e.g., disposed on thebackplane 108). The first physical connector 110 may comprise a firstmedia connector (e.g., male or female connector) that permits thecomputing device module 102 to communicatively couple to the backplane108. Accordingly, the first physical connector 114 may correspond to aphysical connector included by the computing device module 102.Likewise, the second physical connector 116 may comprise a second mediaconnector (e.g., male or female connector) that permits the I/O switchmodule 106 to communicatively couple to the backplane 108. As such, thesecond physical connector 116 may correspond to a physical connectorincluded by the I/O switch module 106.

The retimer 110 may couple the first physical connector 114 with thesecond physical connector 116. For instance, the retimer 110 maycomprise a 25 Gbps fabric retimer. Through this coupling, the retimer110 can permit exchange of data between a computing device module (e.g.,102) coupled to the first physical connector 114 and an I/O switchmodule (e.g., 106) coupled to the second physical connector 116.Depending on the example, the retimer 110 may comprise a retimer capableof supporting a single data I/O type or may comprise an agnostic retimercapable of supporting a plurality of data I/O types. Examples of dataI/O types supported by the retimer 110 can include, without limitation,InfiniBand (e.g., EDR IB), INTEL Omni-Path, Ethernet, and the like. Theretimer 110 may include a transmitter and a receiver, which facilitatesexchange data between the first physical connector 114 and the secondphysical connector 116.

The controller 112 may comprise a microcontroller that includes logic(e.g., machine instructions) or circuitry that causes it to performoperations as described herein. The controller 112 may be one includedby a computer system enclosure that includes the backplane system 104and, further, may be one disposed on the backplane 108. The controller112 may disable the retimer 110 when the backplane system 104transitions from a power off state to a power on state (e.g., initiallypowers-up). Alternatively, the retimer 110 may automatically disableitself when the backplane system 104 transitions from a power off stateto a power on state when a computer device module is initiallyphysically coupled to the second physical connector 114 (e.g., thecomputer device module 102 is replaced with another), or when a I/Oswitch module is initially coupled to the second physical connector 116(e.g., the I/O switch module 106 is replaced with another). With theretimer 110 disabled, the backplane system 104 can prevent a connectionthrough the backplane 108 between the computing device module 102 andthe I/O switch module 106. This connection can be prevented until thebackplane system 104 determines that the connection would involvecompatible data I/O types (e.g., there is a fabric match between thecomputing device module 102 and the I/O switch module 106). For someexamples, the retimer 110 couples the first physical connector 114 tothe second physical connector 116 such that disabling the retimer 110prevents a connection (e.g., data communication) between the computingdevice module 102 and the I/O switch module 106 without preventingsimilar connections between the second physical connector 116 and otherphysical connectors coupled to computing device modules.

The controller 112 may determine a first data I/O type of (e.g.,supported by) the computing device module 102 physically coupled to thefirst physical connector 114. The controller 112 may determine a seconddata I/O type of (e.g., supported by) the I/O switch module 106physically coupled to the second physically connector 116. For someexamples, the controller 112 determines the first data I/O type byreading a read-only memory (ROM, such as EEPROM) included by thecomputing device module 102; the controller 112 may do so when thecomputing device module 102 transitions from a power off state to apower on state (e.g., when it is physically coupled to the backplanesystem 104). Similarly, for some examples, the controller 112 determinesthe second data I/O type by reading ROM included by the I/O switchmodule 106, and may do so when the I/O switch module 106 transitionsfrom a power off state to a power on state (e.g., when it is physicallycoupled to the backplane system 104).

The controller 112 may compare the first determined data I/O type to thesecond determined data I/O type. In response to the first data I/O typematching the second data I/O type, the controller 112 may enable theretimer. With the retimer 110 enabled, the backplane system 104 canpermit a connection through the backplane 108 between the computingdevice module 102 and the I/O switch module 106, thereby permittingcommunication of data between the computing device module 102 and theI/O switch module 106.

For some examples, the backplane system 104 can include an additionalphysical connector (e.g., third physical connector) and an additionalretimer (e.g., second retimer) that couples the additional physicalconnector with the second physical connector 116. When an additionalcomputing device module (e.g., second computing device module) isphysically coupled to the additional physical connector, the additionalcomputing device module and the computing device module 102 physicallycoupled to the first physical connector 114 can exchange data throughthe I/O switch module 106 physically coupled to the second physicalconnector 116. FIG. 2 illustrates such an example computing environment.

FIG. 2 is a block diagram illustrating an example computing environment200 including an example backplane system 204 according to the presentdisclosure. As shown, the example computing environment 200 includes afirst computing device module 202, a backplane system 204, aninput/output (I/O) switch module 206, and a second computing devicemodule 208. The backplane system 204 includes a backplane 210, and afirst retimer 212, a second retimer 214, and a controller 216 forenabling and disabling the retimers (e.g., 212, 214) in response to dataI/O type matches. The backplane 210 includes a first physical connector218, a second physical connector 220, and a third physical connector222. For some examples, the first retimer 212, the second retimer 214,the controller 216, or some combination thereof, are included by thebackplane 210 (e.g., disposed thereon). For instance, the first retimer212 may be disposed on the backplane 210 between the first physicalconnector 218 and the second physical connector 220, and the secondretimer 215 may be disposed on the backplane 210 between the thirdphysical connector 222 and the second physical connector 220.

According to some examples, the first computing device module 202 andthe second computing device module 208 are similar to the computingdevice module 102 described herein with respect to FIG. 1, and the I/Oswitch module 206 is similar to the I/O switch module 106 describedherein with respect to FIG. 1. For some examples, the first physicalconnector 218 and the third physical connectors 222 are similar to thefirst physical connector 114 described herein with respect to FIG. 1,and the second physical connector 220 is similar to the second physicalconnector 116 described herein with respect to FIG. 1. Additionally,with respect to the first computing device module 202, the firstphysical connector 218, the second physical connector 220, and the firstretimer 212, the controller 216 operates similar to how the controller112 is described as operating in FIG. 1 with respect to the computingdevice module 102, the first physical connector 114, the second physicalconnector 116, and the retimer 110.

Unlike FIG. 1, the backplane 210 of FIG. 2 includes the third physicalconnector 222, and the second retimer 214 that couples the thirdphysical connector 222 to the second physical connector 220. For someexamples, the first and second physical connectors 218, 220 are part ofa plurality of physical connectors included by the backplane 210 thatpermit multiple computing device modules to physically couple to thebackplane 210. As with the first physical connector 218 and the secondretimer 214, the controller 216 may disable the second retimer 214 whenthe backplane system 210 transitions from a power off state to a poweron state (e.g., initially powers-up). Alternatively, the second retimer214 may automatically disable itself when the backplane system 210transitions from a power off state to a power on state, when a computerdevice module is initially physically coupled to the third physicalconnector 222 (e.g., the second computing device module 208 is replacedwith another), or when a I/O switch module is initially coupled to thesecond physical connector 220 (e.g., when the I/O switch module 206 isreplaced with another).

With the second retimer 214 disabled, the backplane system 204 canprevent a connection through the backplane 210 between the secondcomputing device module 208 and the I/O switch module 206. As describedherein, this connection can be prevented until the backplane system 204determines that the connection would involve compatible data I/O types(e.g., there is a fabric match between the second computing devicemodule 208 and the I/O switch module 206). For some examples, the secondretimer 214 couples the third physical connector 222 to the secondphysical connector 220 such that disabling the second retimer 214prevents a connection (e.g., data communication) between the secondcomputing device module 208 and the I/O switch module 206 withoutpreventing similar connections between the second physical connector 116and other physical connectors coupled to computing device modules.

FIG. 3 is a block diagram illustrating an example computer systemenclosure 300 including an example backplane system 304 according to thepresent disclosure. For some examples, the backplane system 304 issimilar to the backplane system 104 described with respect to FIG. 1. InFIG. 3, the computer system enclosure 300 includes a front portion 302of the computer system enclosure 300, a rear portion 306 of the computersystem enclosure 300, and the backplane system 304. As shown, the frontportion 302 (e.g., cold aisle) of the computer system enclosure 300 canreceive a computing device module 308, such as a compute tray, and therear portion 306 (e.g., hot aisle) of the computer system enclosure 300can receive an I/O switch module 312, such as a fabric I/O switch. Thecomputing device module 308 comprises read-only memory 320 (e.g.,EEPROM), which can store information regarding the computing devicemodule 308, including a set of data I/O types supported by the computingdevice module 308. Likewise, the I/O switch module 312 comprisesread-only memory 322 (e.g., EEPROM), which can store informationregarding the computing device module 308, including a set of data I/Otypes supported by the computing device module 308.

The backplane system 304 includes a backplane 310, a computing devicebackplane connector 314 disposed on the backplane 310 and configured toreceive a corresponding connector of the compute device module 308, anda switch backplane connector 318 disposed on the backplane 310 andconfigured to receive a corresponding connector of the I/O switch module312. The backplane 310 includes a controller 324, and a retimer 316(e.g., data I/O type agnostic retimer) coupled to each of the computingdevice backplane connector 314, the switch backplane connector 318, andthe controller 324 (e.g., by printed circuit board traces disposed onthe backplane 310). The controller 324 may comprise a microcontroller ofthe computer system enclosure 300.

According to various examples, the controller 324 automatically disablesthe retimer 316 when the backplane 310 powers up (e.g., the computersystem enclosure 300 powers up). With the retimer 316 disabled, thecomputing device module 308 may be prevented from exchanging data withthe I/O switch module 312 through the retimer 316. The controller 324can determine a first data I/O data type supported by the computingdevice module 308, and can do so by reading (326) the ROM 320 of thecomputing device module 308. The controller 324 may read the ROM 320through the computing device backplane connector 314, or anotherconnector (now shown). Similarly, the controller 324 can determine asecond data I/O data type supported by the I/O switch module 312, andcan do so by reading (328) the ROM 322 of the I/O switch module 312. Thecontroller 324 may read the ROM 322 through the switch backplaneconnector 318, or another connector (now shown). The controller 324 canverify whether the first data I/O data type matches the second data I/Otype. If they do match, the controller 324 can enable the retimer 316,thereby permitting the computing device module 308 exchange data withthe I/O switch module 312 through the retimer 316. If they do not match,the controller 324 may set a register bit (e.g., stored within thecontroller 324) to indicate that a data I/O mismatch has been detected.This register bit can be read by firmware or software operating on thecomputer system enclosure 300 (e.g., baseboard management controller orserver management software), which in turn can report the error to auser (e.g., server administrator).

FIG. 4 is a block diagram illustrating an example computing environment400 including an example backplane system 404 according to the presentdisclosure. As shown, the example computing environment 400 includes acomputing device module 402, a backplane system 404, and an input/output(I/O) switch module 406. As also shown, the backplane system 404,includes a backplane 408, and a retimer 410 for enabling and disabling atransmitter of the retimer 410 in response to a data I/O type match.According to some examples, the computing device module 402, the I/Oswitch module 406, the backplane 408, the first physical connector 412,and the second physical connector 414 are respectively similar to thecomputing device module 102, the I/O switch module 106, the backplane108, the first physical connector 114, and the second physical connector116 described herein with respect to FIG. 1. In various examples, thecomponents or the arrangement of components in the backplane system 404may differ from what is depicted in FIG. 4.

Similar to the backplane system 104 of FIG. 1, the backplane system 404may be included within a computer system enclosure (not shown), whichmay be capable of physically receiving the computing device module 402,the I/O switch module 406, or both. The computing device module 402 mayphysically couple to the backplane system 404 when the computing devicemodule 402 is received by (e.g., inserted into) the computer systemenclosure, and the I/O switch module 406 may physically couple to thebackplane system 404 when the I/O switch module 406 received by (e.g.,inserted into) the computer system enclosure. The backplane system 404may be a component of a computer system, such a desktop, laptop,workstation, server (e.g., rack-mount server), or other device operatesby a processor, and a computer system enclosure including the backplanesystem 404 may be part of such a computer system.

In FIG. 4, the retimer 410 includes a transmitter 416 and a receiver418. According to some examples, the transmitter 416 is disabled and thereceiver 418 is enabled (or leaving it enabled if it is already enabled)when the retimer 410 transitions from a power off state to a power onstate. During operation, the retimer 410 may determine, by the receiver418, a first data I/O type of the computing device module 402. For someexamples, while the transmitter 416 is disabled and the receiver 418 isenabled, the receiver 418 (e.g., input physical [PHY] layer) detects thefirst data I/O type from a protocol training or linking sequence (e.g.,to adjust to channel, negotiate speed, or negotiate number of lanes tobe used by the computing device module 402 to communicate with the I/Oswitch module 406) performed by the computing device module 402. Theprotocol training or linking sequence of the computing device module 402may be performed when the backplane system 404 transitions from a poweroff state to a power on state, or when the computing device module 402is physically coupled to the first physical connector 412 (e.g., pluggedinto the backplane system 404).

The retimer 410 may determine, by the receiver 418, a second data I/Otype of the I/O switch module 406. For some examples, while thetransmitter 416 is disabled and the receiver 418 is enabled, thereceiver 418 (e.g., input physical [PHY] layer) detects the second dataI/O type from a protocol training or linking sequence (e.g., to adjustto channel, negotiate speed, or negotiate number of lanes to be used bythe I/O switch module 406 to communicate with the computing devicemodule 402) performed by the I/O switch module 406. The protocoltraining or linking sequence of the I/O switch module 406 may beperformed when the backplane system 404 transitions from a power offstate to a power on state, or when the I/O switch module 406 isphysically coupled to the second physical connector 414 (e.g., pluggedinto the backplane system 404).

In response to the first data I/O type matching the second data I/Otype, the retimer 410 may enable the transmitter 416. Alternatively, inresponse to the first data I/O type mismatching the second data I/Otype, the transmitter 416 may remain disabled and, additionally, may setan error indicator readable by a controller of the backplane system 404.

FIG. 5 is a block diagram illustrating an example computer systemenclosure 500 including an example backplane system 504 according to thepresent disclosure. For some examples, the backplane system 504 issimilar to the backplane system 404 described with respect to FIG. 4. InFIG. 5, the computer system enclosure 500 includes a front portion 502of the computer system enclosure 500, a rear portion 506 of the computersystem enclosure 500, and the backplane system 504. As shown, the frontportion 502 (e.g., cold aisle) of the computer system enclosure 500 canreceive a computing device module 508, such as a compute tray, and therear portion 506 (e.g., hot aisle) of the computer system enclosure 500can receive an I/O switch module 512, such as a fabric I/O switch.

The backplane system 504 includes a backplane 510, a computing devicebackplane connector 514 disposed on the backplane 510 and configured toreceive a corresponding connector of the compute device module 508, anda switch backplane connector 518 disposed on the backplane 510 andconfigured to receive a corresponding connector of the I/O switch module512. The backplane 510 includes a controller 520, and a retimer 516(e.g., data I/O type agnostic retimer) coupled to each of the computingdevice backplane connector 514, the switch backplane connector 518, andthe controller 520 (e.g., by printed circuit board traces disposed onthe backplane 510). The controller 520 may comprise a microcontroller ofthe computer system enclosure 500.

According to various examples, the retimer 516 automatically disablesits transmitter when the backplane 510 powers up (e.g., the computersystem enclosure 500 powers up) or when the retimer 516 powers up.Alternatively, the retimer 516 may disable its transmitter when thecomputing device module 508 is physically coupled to the backplanesystem 504 or when the I/O switch module 512 is physically coupled tothe backplane system 504. The receiver of the retimer 516 can detect thefirst data I/O type of the computing device module 508 during a protocoltraining or linking sequence performed by the computing device module508 (e.g., when the computing device module 508 is physically coupled tothe backplane system 504). The receiver of the retimer 516 can detectthe second data I/O type of the I/O switch module 512 during a protocoltraining or linking sequence performed by the I/O switch module 512(e.g., when the I/O switch module 512 is physically coupled to thebackplane system 504). In response to the first data I/O type matchingthe second data I/O type, the retimer 516 may enable the transmitter ofthe retimer 516. In response to the first data I/O type mismatching thesecond data I/O type, the transmitter of the retimer 516 can remaindisabled. Additionally, in response to the first data I/O typemismatching the second data I/O type, the retimer 516 can send an errorindicator (522) to the controller 520.

FIG. 6 is a flow diagram illustrating an example method 600 for abackplane system according to the present disclosure. In particular, themethod 600 may be performed a controller with respect to a backplanesystem, such as the backplane system 104 of FIG. 1 or the backplanesystem 204 of FIG. 2, or the backplane system 404 of FIG. 4. Althoughexecution of the method 600 is described below with reference to thebackplane system 104 of FIG. 1 and the backplane system 404 of FIG. 4,execution of the method 600 by other suitable systems or devices may bepossible. The method 600 may be implemented in the form of executableinstructions stored on a computer-readable medium or in the form ofelectronic circuitry.

In FIG. 6, the method 600 may begin at block 602, with disablement of aretimer of a backplane system. For some examples, disabling the retimerof the backplane system comprises a controller of the backplane systemdisabled the retimer. For instance, with respect the backplane system104, the controller 112 may disable the retimer 110 of the backplanesystem 104, and may do so when the backplane system 104 transitions to apower on state (e.g., from a power off state). The backplane system 104may transition to a power on state when a computer system enclosureincluding the backplane system is powered on.

For some examples, disabling the retimer of the backplane systemcomprises disabling a transmitter included by the retimer while enablinga receiver of the retimer, thereby permitting the retimer to determinefirst data I/O type and determining the second data I/O type by thereceiver. For instance, with respect to the backplane system 404,disabling the retimer 410 comprise the retimer 410 disabling thetransmitter 416 of the retimer 410 while enabling the receiver 418 ofthe retimer 410 (or leaving it enabled if it is already enabled).

The method 600 may continue to block 604, with a determination of afirst data I/O type of a computing device module coupled to a firstphysical connector. The method 600 may continue to block 606, with adetermination of a second data I/O type of an I/O switch module coupledto a second physical connector. For some examples, the first data I/Otype, the second data I/O type, or both is determined by a retimer of abackplane system. For instance, the receiver 418 of the retimer 410 maydetermine the first data I/O type, the second data I/O type, or both.The receiver 418 may determine the first data I/O type by detecting atraining sequence performed by the computing device module 402, and maydetermine the second data I/O type by detecting a training sequence(e.g., PCI Express training sequence) performed by the I/O switch module406.

For some examples, the first data I/O type, the second data I/O type, orboth is determined by a controller of a backplane system. For instance,the controller 112 may determine the first data I/O type by reading aROM (e.g., EEPROM) of the computer device module 102, and may determinemay determine the second data I/O type by reading a ROM (e.g., EEPROM)of the I/O switch module 106.

The method 600 may continue to block 608, with enablement of the retimerin response to the first data I/O type matching the second data I/Otype.

For some examples, enabling the retimer of the backplane systemcomprises a controller of the backplane system enabling the retimer. Forinstance, the controller 112 can enable the retimer 110 in response tothe first data I/O type matching the second data I/O type.

For some examples, enabling the retimer of the backplane systemcomprises the retimer of the backplane system enabling a transmitter ofthe retimer. For instance, the retimer 410 can enable the transmitter416 of the retimer 410 in response to the first data I/O type matchingthe second data I/O type.

FIG. 7 is a flow diagram illustrating an example method 700 for abackplane system according to the present disclosure. In particular, themethod 700 may be performed a controller with respect to a backplanesystem, such as the backplane system 104 of FIG. 1 or the backplanesystem 204 of FIG. 2, or the backplane system 404 of FIG. 4. Althoughexecution of the method 700 is described below with reference to thebackplane system 104 of FIG. 1 and the backplane system 404 of FIG. 4,execution of the method 700 by other suitable systems or devices may bepossible. The method 700 may be implemented in the form of executableinstructions stored on a computer-readable medium or in the form ofelectronic circuitry.

In FIG. 7, the method 700 may begin at block 702 and may continue toblocks 704, 706, and 708, which may be respectively similar to blocks602, 604, 606, and 608 of the method 600 as described above with respectto FIG. 6. The method 700 may continue to block 710, with setting of anerror indicator in response to the first data I/O type mismatching thesecond data I/O type. For some examples, the error indicator is onereadable by a controller of a computer system enclosure or, morespecifically, a backplane included by the computer system enclosure.Depending on the example, setting the error indicator may comprisesetting an error bit stored in memory or a controller (e.g., register ofthe controller 112). Alternatively, setting an error indicator maycomprise transmitting an error signal to another component that sets(e.g., stores) the error indicator in response to the error signal.

For instance, when the first data I/O type mismatches the second dataI/O type, the retimer 410 may send an error indicator to a controller(e.g., of a backplane system or a computer system enclosure includingthe backplane system). When the first data I/O type mismatches thesecond data I/O type, the retimer 410 may maintain the transmitter 416of the retimer 410 as disabled.

In the foregoing description, numerous details are set forth to providean understanding of the subject disclosed herein. However, variousexamples may be practiced without some or all of these details. Someexamples may include modifications and variations from the detailsdiscussed above. It is intended that the appended claims cover suchmodifications and variations.

The invention claimed is:
 1. A backplane system, comprising: a backplaneincluding a first physical connector to couple with a computing devicemodule, and a second physical connector to couple with an input/output(I/O) switch module; a retimer coupling the first physical connectorwith the second physical connector; and a controller coupled with theretimer, wherein the controller is to: disable a transmitter and enablea receiver of the retimer when the backplane system transitions from apower off state to a power on state; determine a first data I/O type ofthe computing device module; determine a second data I/O type of the I/Oswitch module; and in response to the first data I/O type matching thesecond data I/O type, enable the transmitter of the retimer, wherein thetransmitter remains disabled when the first data I/O type does not matchthe second data I/O type.
 2. The backplane system of claim 1, whereinthe controller is to determine the first data I/O type of the computingdevice module by reading a read-only memory (ROM) of the computingdevice module.
 3. The backplane system of claim 1, wherein thecontroller is to determine the second data I/O type of the computingdevice module by reading a read-only memory (ROM) of the I/O switch. 4.The backplane system of claim 1, wherein the retimer is capable ofsupporting a plurality of data I/O types.
 5. The backplane system ofclaim 1, the backplane including a third physical connector to couplewith a second computing device module, the backplane system comprising asecond retimer coupling the third physical connector with the secondphysical connector, the controller coupled with the second retimer,wherein the controller is to: disable the second retimer when thebackplane system transitions from a power off state to a power on state;determine a third data I/O type of the second computing device module;and in response to the third data I/O type matching the second data I/Otype, enable the second retimer.
 6. A backplane system, comprising: abackplane including a first physical connector to couple with acomputing device module, and a second physical connector to couple withan input/output (I/O) switch module; a retimer coupling the firstphysical connector with the second physical connector, the retimerincluding a transmitter and a receiver, the transmitter being disabledand the receiver being enabled when the retimer transitions from a poweroff state to a power on state, wherein the retimer is to: determine, bythe receiver, a first data I/O type of the computing device module;determine, by the receiver, a second data I/O type of the I/O switchmodule; and in response to the first data I/O type matching the seconddata I/O type, enable the transmitter, wherein the transmitter remainsdisabled when the first data I/O type does not match the second data I/Otype.
 7. The backplane system of claim 6, wherein in response to thefirst data I/O type mismatching the second data I/O type, the retimer isto set an error indicator readable by a controller of the backplanesystem.
 8. The backplane system of claim 6, wherein the retimerdetermines the first data I/O type by detecting a training sequenceperformed by the computing device module.
 9. The backplane system ofclaim 6, wherein the retimer determines the second data I/O type bydetecting a training sequence performed by the I/O switch module.
 10. Amethod, comprising: disabling a transmitter and enable a receiver of aretimer of a backplane system, the retimer coupling a first physicalconnector of the backplane system to a second physical connector of thebackplane system; determining a first data input/output (I/O) type of acomputing device module coupled with the first physical connector;determining a second data I/O type of an I/O switch module coupled withthe second physical connector; and in response to the first data I/Otype matching the second data I/O type, enabling the transmitter of theretimer, wherein the transmitter remains disabled when the first dataI/O type does not match the second data I/O type.
 11. The method ofclaim 10, wherein disabling the retimer of the backplane systemcomprises a controller of the backplane system disabling the retimer.12. The method of claim 10, wherein determining the first data I/O typeand determining the second data I/O type are determined by the receiverof the retimer.
 13. The method of claim 10, comprising in response tothe first data I/O type mismatching the second data I/O type, setting anerror indicator readable by a controller of the backplane system. 14.The method of claim 10, wherein the first data I/O type and the seconddata I/O type are determined by the retimer.
 15. The method of claim 10,wherein the first data I/O type and the second data I/O type aredetermined by a controller of the backplane system.
 16. The backplanesystem of claim 1, wherein an entirety of the retimer is disabled whenthe transmitter and the receiver of the retimer are disabled.
 17. Thebackplane system of claim 1, wherein the retimer is a first retimer, andthe system further comprises a second retimer that disables itself. 18.The backplane system of claim 17, wherein the second retimer disablesitself when the backplane system transitions from a power off state to apower on state.
 19. The backplane system of claim 17, wherein the secondretimer disables itself when the computing device module is initiallyphysically coupled to a third physical connector and a second computingdevice module is replaced with another.
 20. The backplane system ofclaim 17, wherein the second retimer disables itself when the I/O switchmodule is initially physically coupled to the second physical connectorand the I/O switch module is replaced with another.